Lens driving apparatus and method of manufacturing the lens driving apparatus

ABSTRACT

A lens drive device has (i) an objective lens and (ii) a lens holder, to a side face of which coils for drive control are attached. The surface where the coils are adhered, or the side surface, is an irregular surface where a recess/projection section for restricting the direction of flow of an adhesive is formed. The coils and the lens holder are integrally formed together by the adhesive with the recess/projection section in between.

This application is the U.S. national phase of International ApplicationNo. PCT/JP2006/316710, filed 25 Aug. 2006, the entire contents of whichis hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to the structure of a lens drivingapparatus of a disc player for recording information onto a disc-shapedrecording medium and reading the recorded information, and a method ofmanufacturing the lens driving apparatus.

BACKGROUND ART

There is known such a lens driving apparatus that drives an objectivelens in a lens optical axis direction (or focus direction) in order tofocus a reading beam on a disc surface, that drives the objective lensin an orthogonal direction (or tracking direction) orthogonal to thelens optical axis direction in order to make the reading beam follow aninformation track, and that drives the objective lens in a warpingdirection (or tilt direction) of the disc surface in order to irradiatethe disc surface with the reading beam with the optical axis of thereading beam being perpendicular to the disc surface, when informationis read from a disc on which the information is optically recorded. Oneexample of such a lens driving apparatus is disclosed in a patentdocument 1 or the like. The lens driving apparatus is of a print coiltype in which a planar coil substrate, formed by patterning and etchinga focus coil and a tracking coil, is fixed by an adhesive to the bothside surfaces of a lens holder with a built-in objective lens.

Patent document 1: Japanese Patent Application Laid Open NO. 2001-229557

Patent document 2: Japanese Patent Application Laid Open NO. 2006-31759

DISCLOSURE OF INVENTION Subject to be Solved by the Invention

The aforementioned lens driving apparatus, however, has such a technicalproblem that if the flowing direction of an adhesive is not controlledwhen the coils and the both side surfaces of the lens holder areintegrally molded, there arise variations in the flowing direction ofthe adhesive, adhesive distribution, and adhesive thickness, between theadhesive surface of the coil and the side surfaces of the lens holder.Thus if a driving force is applied to the integrally molded lens holder,for example, there is a significant influence on vibration such aspitching resonance (or secondary resonance) corresponding to the focusdirection, leading to reduction in quality of servo control anddeterioration in quality of information reading or writing with respectto a disc-shaped recording medium, which is technically a problem.

In view of the aforementioned problem, it is therefore an object of thepresent invention to provide a lens driving apparatus which allows moreappropriate integral molding of the coils and the side surfaces of thelens holder, and a method of manufacturing the lens driving apparatus.

Means for Solving the Subject

The above object of the present invention can be achieved by a lensdriving apparatus according to claim 1 provided with at least a lensholder (i) which has an objective lens; and (ii) in which a coil fordriving control is mounted on side surface thereof, either an adhesivesurface of the coil and the side surface being a concavo-convex surfaceon which a concavo-convex part for controlling a flowing direction of afluid adhesive, is formed, the coil and the lens holder being integrallymolded by the adhesive via the concavo-convex surface.

The above object of the present invention can be also achieved by amethod of manufacturing a lens driving apparatus according to claim 8provided with at least a lens holder (i) which has an objective lens;and (ii) in which a coil for driving control is mounted on side surfacethereof, the method provided with: a concavo-convex forming process offorming either an adhesive surface of the coil and the side surface as aconcavo-convex surface on which a concavo-convex part for controlling aflowing direction of a fluid adhesive, is formed; and an integralmolding process of integrally molding the coil and the lens holder bythe adhesive via the concavo-convex surface.

The operation and other advantages of the present invention will becomemore apparent from the embodiments explained below.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an explanation will be given on a lens driving apparatusand a method of manufacturing the lens driving apparatus in embodimentof the present invention as the best mode for carrying out the presentinvention.

Embodiment of Lens Driving Apparatus

An embodiment of the lens driving apparatus of the present invention isa lens driving apparatus provided with at least a lens holder (i) whichhas an objective lens; and (ii) in which a coil for driving control ismounted on side surface thereof, either an adhesive surface of the coiland the side surface being a concavo-convex surface on which aconcavo-convex part for controlling a flowing direction of a fluidadhesive, is formed, the coil and the lens holder being integrallymolded by the adhesive via the concavo-convex surface.

According to the embodiment of the lens driving apparatus of the presentinvention, in general, a magnetic field is formed between a pair ofmagnets by oppositely placing the pair of magnets at a predetermineddistance. By electrically charging the coil such as a FP (Fine Pattern)coil, mounted on the side surfaces of the lens holder having theobjective lens in the magnetic field, the lens holder, which is held bya pair of linear elastic members fixed to the support part of the lensdriving apparatus, is inclined and is displaced in the focus directionand the tracking direction.

In particular, in the embodiment, either the adhesive surface of thecoil or the side surfaces of the lens holder is the concavo-convexsurface on which the concavo-convex part for controlling the flowingdirection of the fluid adhesive is formed, and the coil and the lensholder are integrally molded by the adhesive via or through theconcave-convex surface.

If the flowing direction of the adhesive is not controlled in theintegral molding of the coil and the side surfaces of the lens holder inthe objective lens driving apparatus, there arise variations in theflowing direction of the adhesive, distribution of the adhesive, andthickness of the adhesive, between the adhesive surface of the coil andthe side surfaces of the lens holder. Thus if a driving force is appliedto the integrally molded lens holder, for example, there is asignificant influence on vibration such as pitching resonance (orsecondary resonance) corresponding to the focus direction.

In contrast, in the embodiment, the flowing direction of the adhesive iscontrolled in the integral molding of the coil and the side surfaces ofthe lens holder. Thus even if the driving force is applied to theintegrally molded lens holder in the focus direction, in the trackingdirection, or in the tilt direction, it is possible to reduce oreliminate the influence on the vibration such as pitching resonance,more effectively. As a result, in addition to improving the quality ofservo control, it is possible to improve the quality of reading ofsignal or writing of signal with respect to a disc-shaped recordingmedium.

In one aspect of the embodiment of the lens driving apparatus of thepresent invention, a concavo-convex shape pattern of the concavo-convexsurface is defined on the basis of (i) a position at which the adhesiveis injected, (ii) a direction in which the adhesive is injected, or(iii) the flowing direction of the adhesive in the integral molding.

According to this embodiment, in the integral molding of the coil andthe side surfaces of the lens holder, the flowing direction of theadhesive is controlled on the basis of the aforementioned concavo-convexshape pattern. Therefore, even if the driving force is applied to theintegrally molded lens holder in the focus direction, in the trackingdirection, or in the tilt direction, it is possible to reduce oreliminate the influence on the vibration such as pitching resonance,more effectively.

In another aspect of the embodiment of the lens driving apparatus of thepresent invention, a concavo-convex shape pattern of the concavo-convexsurface is defined on the basis of a tracking direction, a focusingdirection, or a tilt direction in which the lens holder is driven.

According to this aspect, the concavo-convex shape pattern iscontrolled, for example, on the basis of the amount of the adhesive(i.e. adhesive force) required on the basis of the focus direction, thetracking direction, or the tilt direction. Therefore, even if thedriving force is applied to the integrally molded lens holder in thefocus direction, in the tracking direction, or in the tilt direction, itis possible to reduce or eliminate the influence on the vibration suchas pitching resonance, more effectively.

In another aspect of the embodiment of the lens driving apparatus of thepresent invention, (i) a first convex part in a relatively long shape ina tracking direction and (ii) a second convex part in a relatively longshape in a focusing direction, are formed on the concavo-convex surface.

According to this aspect, in the integral molding of the coil and theside surfaces of the lens holder, the flowing direction of the adhesiveis controlled on the basis of the aforementioned first convex part andsecond convex part. Therefore, even if the driving force is applied tothe integrally molded lens holder in the focus direction, in thetracking direction, or in the tilt direction, it is possible to reduceor eliminate the influence on the vibration such as pitching resonance,more effectively.

In another aspect of the embodiment of the lens driving apparatus of thepresent invention, (i) a first convex part in a relatively long shape ina tracking direction and (ii) a second convex part for making theconcavo-convex surface substantially parallel to an optical axis of theobjective lens, are formed on the concavo-convex surface.

According to this aspect, on the basis of the first convex part and thesecond convex part having substantially the same thickness as the firstconvex part, it is possible (i) to make the convex-concavo surfaceparallel to the optical axis of the objective lens and (ii) to hold theintegrally molded lens holder substantially perpendicular to the opticalaxis without any force applied from the exterior. As a result, it ispossible to omit a force for making the integrally molded lens holdersubstantially parallel to the optical axis, and it is also possible toeffectively reduce the electric power consumption of control currentprovided for the coil in order to perform various servo control.

In another aspect of the embodiment of the lens driving apparatus of thepresent invention, (i) a convex part located in a substantially centralportion in a tracking direction and (ii) two concave parts formed withthe convex part therebetween, are formed on the concavo-convex surface.

According to this aspect, it is possible to effectively control theadhesive, injected at line-symmetric positions, not to randomly diffuseand flow, on the basis of the convex part located in the central portionand the concave parts located on the both sides, which are disposedsubstantially line-symmetrically. As a result, with regard to the lensholder, it is possible (i) to increase the area size of the adhesivesurface on the basis of the adhesive injected at the line-symmetricpositions, (ii) to control the flowing direction of the adhesive morehighly accurately, and (iii) to increase an adhesive force in theintegral molding.

In another aspect of the embodiment of the lens driving apparatus of thepresent invention, the concavo-convex surface is formed on the basis ofmasking process, which varies a position and light intensity of anirradiated laser beam; and an etching process, on the adhesive surfaceof the coil or the side surface, on which a photosensitive resin (orphotoresist) is applied doubly or in a two-layer manner.

According to this aspect, the concavo-convex part can be formed morehighly accurately on the basis of the masking process and the etchingprocess on the concavo-convex surface on which the photosensitive resinis applied doubly or in the two-layer manner.

Embodiment of Method of Manufacturing a Lens Driving Apparatus

An embodiment of the method of manufacturing a lens driving apparatus ofthe present invention is a method of manufacturing a lens drivingapparatus provided with at least a lens holder (i) which has anobjective lens; and (ii) in which a coil for driving control is mountedon side surface thereof the method provided with: a concavo-convexforming process of forming either an adhesive surface of the coil andthe side surface as a concavo-convex surface on which a concavo-convexpart for controlling a flowing direction of a fluid adhesive, is formed;and an integral molding process of integrally molding the coil and thelens holder by the adhesive via the concavo-convex surface.

According to the embodiment of the method of manufacturing a lensdriving apparatus of the present invention, firstly, in theconcavo-convex forming process, either the adhesive surface of the coilfor driving control or the side surfaces of the lens holder is formed asthe concavo-convex surface on which the concavo-convex part forcontrolling the flowing direction of the fluid adhesive is formed.

Then, in the integral molding process, the coil for driving control andthe lens holder are integrally molded by the adhesive via theaforementioned concavo-convex surface.

As a result, it is possible to simply and appropriately manufacture thelens driving apparatus provided with the lens holder in which the coilfor driving control and the lens holder are integrally molded by theadhesive via the concavo-convex surface on which the concavo-convex partfor controlling the flowing direction of the fluid adhesive is formed.

Incidentally, in response to the various aspects of the aforementionedembodiment of the lens driving apparatus of the present invention, theembodiment of the method of manufacturing the lens driving apparatus ofthe present invention can also employ various aspects.

In one aspect of the embodiment of the method of manufacturing a lensdriving apparatus of the present invention, the concavo-convex formingprocess forms the concavo-convex surface on the basis of (i) an applyingprocess of applying a photosensitive resin (or photoresist) doubly or ina two-layer manner; (ii) a masking process, which varies a position andlight intensity of an irradiated laser beam; and (iii) an etchingprocess.

According to this aspect, the concavo-convex forming process is providedwith the following three processes along time series, in order to formthe aforementioned concavo-convex shape pattern of the concavo-convexsurface. Firstly, in (i) the applying process, the photosensitive resin(or photoresist) is applied doubly or in the two-layer manner on eitherthe adhesive surface of the coil for driving control or the sidesurfaces of the lens holder. Then, in (ii) the masking process, forexample, a laser beam is irradiated in changing a position of anirradiation and light intensity, on the basis of photomasking. In theposition or area irradiated with the laser beam, the second-layerphotoresist, which is outer side of the doubly applied photoresist, isexposed. Then, in (iii) the etching process, the concavo-convex surfaceis formed by dipping the surface in a developer.

As a result, it is possible to more simply and highly accuratelymanufacture the lens driving apparatus in which the coil for drivingcontrol and the lens holder are integrally molded by the adhesive viathe concavo-convex surface on which the concavo-convex part forcontrolling the flowing direction of the fluid adhesive, is formed.

The operation and other advantages of the present invention will becomemore apparent from the examples explained below.

As explained above, according to the embodiment of the lens drivingapparatus of the present invention, it is provided with at least: (i) anobjective lens; and (ii) a lens holder in which a coil for drivingcontrol is mounted on side surfaces thereof, either an adhesive surfaceof the coil and the side surfaces being a concavo-convex surface onwhich a concavo-convex part for controlling a flowing direction of afluid adhesive is formed, the coil and the lens holder being integrallymolded by the adhesive via the concavo-convex surface. As a result,since the flowing direction of the adhesive is controlled in theintegral molding of the coil and the side surfaces of the lens holder,even if the driving force in the focus direction, the trackingdirection, or the tilt direction is applied to the integrally moldedlens holder, it is possible to reduce or eliminate the influence on thevibration such as pitching resonance, more effectively. As a result, inaddition to improving the quality of servo control, it is possible toimprove the quality of information reading or writing with respect to adisc-shaped recording medium.

Moreover, according to the embodiment of the method of manufacturing thelens driving apparatus of the present invention, it is provided with theconcavo-convex forming process and the integral molding process. As aresult, it is possible to simply and appropriately manufacture the lensdriving apparatus provided with the lens holder in which the coil fordriving control and the lens holder are integrally molded by theadhesive via the concavo-convex surface on which the concavo-convex partfor controlling the flowing direction of the fluid adhesive is formed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 are a plan view (FIG. 1( a)) and a side view (FIG. 1( b)) showingthe basic structure of a lens driving apparatus 150 in an example of thepresent invention.

FIG. 2 are a plan view schematically showing a concavo-convex shapepattern formed on either a adhesive surface of the coil or side surfacesof a lens holder in the example (FIG. 2( a)) and a plan viewschematically showing either the adhesive surface of the coil or theside surfaces of the lens holder in a comparison example (FIG. 2( b)).

FIG. 3 are one and another plan views schematically showing theconcavo-convex shape pattern formed on either the adhesive surface ofthe coil or the side surfaces of the lens holder in modified examples(FIG. 3( a) and FIG. 3( b)).

FIG. 4 is a schematic diagram schematically showing a manufacturingprocedure of manufacturing the lens driving apparatus of the presentinvention in time series.

DESCRIPTION OF REFERENCE CODES

-   10 actuator base-   11, 12 magnet-   20 support base-   21 support wire-   22 a drawing part-   22 b connection part-   30 lens holder-   80, 90 coil substrate-   100 movable part

EXAMPLE

Hereinafter, the preferred embodiments of the present invention will beexplained with reference to the drawings.

(1) Basic Structure

Next, with reference to FIG. 1, the basic structure of a lens drivingapparatus 150 in an example of the present invention will be explained.

(1-1) General Structure

Firstly, the general structure of the lens driving apparatus 150 will beexplained with reference to FIG. 1. FIG. 1 are a plan view (FIG. 1( a))and a side view (FIG. 1( b) showing the basic structure of the lensdriving apparatus 150 in the example of the present invention.

As shown in FIG. 1( a) and FIG. 1( b), in the lens driving apparatus 150in the example of the present invention, a pair of L-shaped yokes 13 towhich a magnet 11 or 12 for magnetic-field formation is fixed isoppositely placed with a predetermined magnetic gap on a plate-likeactuator 10, and fixed to the actuator base 10 by a plurality of screws14. Moreover, a support base 20 is fixed on the actuator base 10 by thescrews 14, and four support wires 21 of the support base 20 support amovable part 100, inclinably at a position where the movable body 100 issandwiched between the magnets 11 and 12, and movably in the verticaland horizontal directions.

The movable part 100 is provided with a substantially square lens holder30 which houses an objective lens 31 therein; a coil substrate 80 fixedby an adhesive or the like to the side surface in a jitter direction (anarrow J in FIG. 1) of the lens holder 30 facing the magnet 11; and acoil substrate 90 fixed by an adhesive or the like to the side surfacein the jitter direction of the lens holder 30 facing the magnet 12. Fourholding parts 32 a and 32 b, formed and protruding in the trackingdirection (an arrow T in FIG. 1) of the lens holder 30, are supported bythe four support wires 21. By this, the movable part 100 is supported,inclinably and movably in the focus direction (an arrow F in FIG. 1) andin the tracking direction.

The support wire 21 is made of a rod-like or plate-like conductiveelastic member. One end of each support wire 21 is rolled and extendedto form a drawing part 22 a, and one portion of each support wire 21 isintegrally molded within the support base 20 by outsert molding or thelike in the molding of the support base 20. The other end of eachsupport wire 21 is similarly rolled and extended to form a connectionpart 22 b and fixed by an adhesive or the like to respective one of thefour holding devices 32 a and 322 b disposed on the lens holder 30.

By oppositely placing the magnets 11 and 12 at a predetermined distance,a magnetic field is formed between the magnets 11 and 12. Byelectrically charging a coil for tilt control, a coil for focus control,and a coil for tracking control located on the coil substrates 80 and 90fixed to the lens holder 30 in this magnetic field, the movable part 100is inclined and is displaced in the focus direction and the trackingdirection.

(2) Detailed Structure of Embodiment and Study of Operation and Effect

Next, with reference to FIG. 2, an explanation will be given on thedetailed structure of the embodiment, and the study of the operation andeffect. FIG. 2 are a plan view schematically showing an concavo-convexshape pattern formed on either a adhesive surface of the coil or sidesurfaces of a lens holder in the example (FIG. 2( a)) and a plan viewschematically showing either the adhesive surface of the coil or theside surfaces of the lens holder in a comparison example (FIG. 2( b)).Incidentally, in FIG. 2 and FIG. 3 described later, as shown by thearrows, the vertical direction i.e. direction which is toward upper sideto lower side or the lower side to the upper side, indicates the focusdirection, and the horizontal direction i.e. direction which is towardright direction to left direction or the left direction to the rightdirection, indicates the tracking direction. Moreover, in FIG. 2 andFIG. 3 described later, as one example, a convex part 81 may be formedon the adhesive surface of the coil substrate, or the convex part 81 maybe formed on the side surfaces of the lens holder 30.

Specifically, as shown in FIG. 2( a), on the basis of the U-shapedconvex part 81, which is relatively long in the tracking direction andwhich is formed on either the adhesive surface of the coil or the sidesurfaces of the lens holder, an adhesive is controlled not to randomlyflow and diffuse toward the central portion. Because the adhesive isinjected at each of the two points on the right and left sides from theupper side to the lower side in the focus direction.

If, as shown in FIG. 2( b), the flowing direction of the adhesive is notcontrolled in the integral molding of the coils and the side surfaces ofthe lens holder in the objective lens driving apparatus, there arisevariations in the flowing direction of the adhesive, distribution of theadhesive, and thickness of the adhesive, between the adhesive surface ofthe coil and the side surfaces of the lens holder. Thus if a drivingforce is applied to the integrally molded lens holder for example, thereis a significant influence on vibration such as pitching resonance (orsecondary resonance) corresponding to the focus direction.

In contrast, in the example, the flowing direction of the adhesive iscontrolled on the basis of the U-shaped convex part 81 in the integralmolding of the coils and the side surfaces of the lens holder, so evenif the driving force is applied to the integrally molded lens holder inthe focus direction, in the tracking direction, or in the tiltdirection, it is possible to reduce or eliminate the influence on thevibration such as pitching resonance, more effectively. As a result, inaddition to improving the quality of servo control, it is possible toimprove the quality of reading of signal or writing of the signal withrespect to the disc-shaped recording medium.

(3) Modified Examples

Next, with reference to FIG. 3, modified examples of the presentinvention will be explained. FIG. 3 are one and another plan views (FIG.3( a) and FIG. 3( b)) schematically showing the concavo-convex shapepattern formed on either the adhesive surface of the coil or the sidesurfaces of the lens holder in modified examples.

In one modified example of the example, as shown in FIG. 3( a), twoelongated, rectangular shaped convex parts 82 a and 82 b are formed onthe adhesive surface of the coil substrate 80. Therefore, on the basisof the convex parts 82 a and 82 b, an adhesive can be effectivelycontrolled not to randomly flow and diffuse toward the substantiallycentral portion. Because the adhesive is injected at each of the twopoints on the right and left sides from the upper side to the lower sidein the focus direction.

In particular, the convex part 82 b located on the lower side in thefocus direction, is preferably substantially as thick as the convex part82 a located on the upper side in the focus direction. Therefore, it ispossible (i) to make the adhesive surface of the coil and the sidesurfaces of the lens holder parallel to the optical axis of theobjective lens and (ii) to hold the integrally molded lens holdersubstantially perpendicular to the optical axis without any forceapplied from the exterior. As a result, it is possible to omit a forcefor making the integrally molded lens holder substantially parallel tothe optical axis, and it is also possible to effectively reduce theelectric power consumption of control current provided for the coils inorder to perform various servo control.

In another modified example of the example, as shown in FIG. 3( b), aplurality of rectangular shaped convex parts 33 a, 83 b, 83 c, and 83 d,formed on the adhesive surface of the coil substrate 80, are arrangedsubstantially line-symmetrically in the focus direction. Therefore, onthe basis of the convex parts 83 a, 83 b, 83 c, and 83 d, an adhesivecan be effectively controlled not to randomly flow and diffuse. Becausethe adhesive is injected at each of the three points on the central,right, and left sides, from the upper side to the lower side in thefocus direction. As a result, with regard to the lens holder, it ispossible (i) to increase a area size of the adhesive surface on thebasis of the adhesive injected from the separated three points, (ii) tocontrol the flowing direction of the adhesive more highly accurately,and (iii) to increase an adhesive force in the integral molding. It isadditionally noted that specifically, according to the study by thepresent inventors, it is possible to increase the adhesive force usingcapillarity, caused on the basis of fluidity of the adhesive passingthrough a gap on the adhesive surface, by arranging concave parts orconvex parts line-symmetrically.

In particular, the convex parts 83 b and 83 d located on the lower sidein the focus direction are preferably arranged line-symmetrically andare preferably substantially as thick as the convex parts 83 a and 83 clocated on the upper side in the focus direction. Therefore, it ispossible (i) to make the adhesive surface of the coil and the sidesurfaces of the lens holder parallel to the optical axis of theobjective lens and (ii) to hold the integrally molded lens holdersubstantially perpendicular to the optical axis without any forceapplied from the exterior.

(4) Manufacturing Method (or Manufacturing Procedure)

Next, with reference to FIG. 4, an explanation will be given on amanufacturing method (or manufacturing procedure) of the lens drivingapparatus in the example, including a study of the operation and effectthereof. FIG. 4 is a schematic diagram schematically showing amanufacturing procedure of manufacturing the lens driving apparatus ofthe present invention, in time series.

As shown in FIG. 4, firstly, in order to form a concavo-convex shapepattern on a concavo-convex surface on which the concavo-convex part forcontrolling the flowing direction of the fluid adhesive by aconcavo-convex forming process, a photosensitive resin (e.g.photoresist) is applied doubly or in a two-layer manner, on either theadhesive surface of the coil for driving control or the side surfaces ofthe lens holder, in an applying process. Specifically, as shown in aStep 1 in FIG. 4, a viscous photosensitive resin is dropped and appliedwith a uniform thickness as the first layer, and as shown in a Step 2 inFIG. 4, the photosensitive resin is again dropped and applied with auniform thickness as the second layer.

Then, in a masking process, for example, a laser beam is irradiated inchanging a position of an irradiation and light intensity, on the basisof photomasking or photo-masking method. In the position or areairradiated with the laser beam, the photoresist of the second-layer isexposed. The photoresist of the second-layer is outer side of the doublyapplied photoresist.

Then, in an etching process, the concavo-convex surface is formed bydipping the surface in a developer. Specifically, as shown in a Step 3in FIG. 4, for example, an area which is not covered by a photomask, isirradiated with the laser beam such as an electron beam or ultravioletwith a predetermined laser power. Then, as shown in a Step 4 in FIG. 4,in the portion irradiated with the laser beam, the bond of thephotoresist is cut by light energy at the molecule level, so dipping thesurface in the developer provides a space, and the concave parts of theconcavo-convex part, are formed. In particular, the size of the concavepart can be determined depending on the beam radius of the laser beam,in addition to the control of the irradiation position of the laser beamand the control of the laser power. Moreover, the depth of the concavepart can be determined depending on the thickness of the photoresist, inaddition to the laser power. Incidentally, the laser power desirablyappropriately corresponds to the sensitivity of the photoresist.

Then, as shown in a Step 5 in FIG. 4, in an integral molding process,one and the other of (i) the adhesive surface of the coil for drivingcontrol and (ii) the side surfaces of the lens holder are integrallymolded by injecting an adhesive in the aforementioned concave parts.

Consequently, according to the example, it is possible to more simplyand highly accurately manufacture the lens driving apparatus in which(i) the coil for driving control and (ii) the lens holder are integrallymolded by an adhesive via the concavo-convex surface on which theconcavo-convex part for controlling the flowing direction of the fluidadhesive is formed.

The present invention is not limited to the aforementioned embodiment,but various changes may be made, if desired, without departing from theessence or spirit of the invention which can be read from the claims andthe entire specification. A lens driving apparatus and a method ofmanufacturing the lens driving apparatus, all of which involve suchchanges, are also intended to be within the technical scope of thepresent invention.

INDUSTRIAL APPLICABILITY

The lens driving apparatus and a method of manufacturing the lensdriving apparatus according to the present invention can be applied to alens driving apparatus for reproducing an information recording mediumsuch as an optical disc, and a method of manufacturing the lens drivingapparatus.

1. A lens driving apparatus comprising at least a lens holder (i) whichhas an objective lens; and (ii) in which a coil for driving control ismounted on side surface thereof, either an adhesive surface of the coiland the side surface being a concavo-convex surface on which aconcavo-convex part for controlling a flowing direction of a fluidadhesive, is formed, the concavo-convex part for controlling theadhesive which is injected from an upper side to a lower side in avertical direction, not to flow toward a substantially central portion,being formed at each of both edges in a horizontal direction on theconcavo-convex surface, the coil and the lens holder being integrallymolded by the adhesive via the concavo-convex surface, wherein (i) afirst convex part in a relatively long shape in a tracking direction and(ii) a second convex part in a relatively long shape in a focusingdirection, are formed on the concavo-convex surface.
 2. A lens drivingapparatus comprising at least a lens holder (i) which has an objectivelens; and (ii) in which a coil for driving control is mounted on sidesurface thereof, either an adhesive surface of the coil and the sidesurface being a concavo-convex surface on which a concavo-convex partfor controlling a flowing direction of a fluid adhesive, is formed, theconcavo-convex part for controlling the adhesive which is injected froman upper side to a lower side in a vertical direction, not to flowtoward a substantially central portion, being formed at each of bothedges in a horizontal direction on the concavo-convex surface, the coiland the lens holder being integrally molded by the adhesive via theconcavo-convex surface, wherein (i) a first convex part in a relativelylong shape in a tracking direction and (ii) a second convex part formaking the concavo-convex surface substantially parallel to an opticalaxis of the objective lens, are formed on the concavo-convex surface. 3.A lens driving apparatus comprising at least a lens holder (i) which hasan objective lens; and (ii) in which a coil for driving control ismounted on side surface thereof, either an adhesive surface of the coiland the side surface being a concavo-convex surface on which aconcavo-convex part for controlling a flowing direction of a fluidadhesive, is formed, the concavo-convex part for controlling theadhesive which is injected from an upper side to a lower side in avertical direction, not to flow toward a substantially central portion,being formed at each of both edges in a horizontal direction on theconcavo-convex surface, the coil and the lens holder being integrallymolded by the adhesive via the concavo-convex surface, wherein (i) aconvex part located in a substantially central portion in a trackingdirection and (ii) two concave part formed with the convex parttherebetween, are formed on the concavo-convex surface.
 4. The lensdriving apparatus according to claim 1, wherein the concavo-convexsurface is formed on the basis of masking process, which varies aposition and light intensity of an irradiated laser beam; and an etchingprocess, on the adhesive surface of the coil or the side surface, onwhich a photosensitive resin is applied doubly or in a two-layer manner.5. The lens driving apparatus according to claim 2, wherein theconcavo-convex surface is formed on the basis of masking process, whichvaries a position and light intensity of an irradiated laser beam; andan etching process, on the adhesive surface of the coil or the sidesurface, on which a photosensitive resin is applied doubly or in atwo-layer manner.
 6. The lens driving apparatus according to claim 3,wherein the concavo-convex surface is formed on the basis of maskingprocess, which varies a position and light intensity of an irradiatedlaser beam; and an etching process, on the adhesive surface of the coilor the side surface, on which a photosensitive resin is applied doublyor in a two-layer manner.
 7. A method of manufacturing a lens drivingapparatus comprising at least a lens holder (i) which has an objectivelens; and (ii) in which a coil for driving control is mounted on sidesurface thereof, said method comprising: a concavo-convex formingprocess of forming either an adhesive surface of the coil and the sidesurface as a concavo-convex surface on which a concavo-convex part forcontrolling a flowing direction of a fluid adhesive, is formed; and anintegral molding process of integrally molding the coil and the lensholder by the adhesive via the concavo-convex surface, saidconcavo-convex forming process forming the concavo-convex part forcontrolling the adhesive which is injected from an upper side to a lowerside in a vertical direction, not to flow toward a substantially centralportion at each of both edges in a horizontal direction on theconcavo-convex surface, wherein said concavo-convex forming processforms the concavo-convex surface on the basis of (i) an applying processof applying a photosensitive resin doubly or in a two-layer manner; (ii)a masking process, which varies a position and light intensity of anirradiated laser beam; and (iii) an etching process.
 8. The lens drivingapparatus according to claim 1, wherein a concavo-convex pattern of theconcavo-convex surface is defined on the basis of a tracking direction,a focusing direction, or a tilt direction in which the lens holder isdriven.
 9. The lens driving apparatus according to claim 2, wherein aconcavo-convex pattern of the concavo-convex surface is defined on thebasis of a tracking direction, a focusing direction, or a tilt directionin which the lens holder is driven.
 10. The lens driving apparatusaccording to claim 3, wherein a concavo-convex pattern of theconcavo-convex surface is defined on the basis of a tracking direction,a focusing direction, or a tilt direction in which the lens holder isdriven.